Blower for annealing furnaces and the like



Dec. 31,1940.

0. WECHSBERG ETAL BLOWER FOR ANNEALING FURNACES AND THE LIKE Filed March7,: 1938 2 Sheets-Sheet 1 inf/5722271)? 0.77c/Z5 2 Sheets-Sheet 2 FiledMarch '7, 1938 O. WECHSBERG ETAL BLOWER "FOR ANNEALING FURNACES AND THELIKE Dec. 31, 194-0.

latented Dec. 3 1, 1940 UNITED 2,226,986 PATENT OFFICE I I .nmwsaFORANNEAIJNG summons I AND'THELIKE Weehsberg' and Helm'ut Werner,Worcester, mm, assignors to Coppus Engineering Corporation; -Worcester,Mass" a. corporation of Massnchusetts,

Q application March i, 193s,'seria1 No. 194,383 in Claims. ,(ct 230-209)The present invention invention relates, to a. h Fig. l.-is a verticalsectional view through a blower especially for useindistributingor cir+-culating the hot gases inannealing iurnaces, and is particularlydirected to'a blower. in which the driving mechanism is kept at asuitable operat ing temperature by the-circulation of a cooling fluid.This is a continuation in part of our co.-;

pending application, Serial No. 126,262, filed Feb-1 ruary 17, 1937, for-Blower for annealing furnaces and the like.

the driving mechanism, which mayfbe suitable gearing or a driving motor.Itis obvious that' too much heat in the bearings ordrivingmech- 1 anismwill detrimentally afieot the operation and life of the blower, and itis accordingly the prin-g cipal object of the present invention toprovide for so completely cooling the driving shaft for the fan, thatthe bearings for the shaft will not become overheated and that thedriving mechq anism may not be affected by'theconducted heat. 1 1

In carrying out the objects of the invention the essential feature is toprovide for the circulation of sufficient fluid around or through thedrive shaft between the fan on'the-end thereof and the supportingstructure, so that the heat transmitted along the shaftmay be entirelydissipated and. thereby keep the portions of thei shaft adjacent to thebearings and driving niech anism at a relatively low temperature: This.cooling action must be obtained without any connection to the interiorof the furnace or oven,

and the fan must beso arranged that there will be no substantial leakageof the-gas "from with in the furnace by passing around the fan shafte orthe supporting structuretherefon Where the bearings are cooled byia,structure functioning only while the blowe gis iiin operation, there isthe danger of damage to the bearf ings upon failure of thedriving-.mechanism for the blower Thus a further object ofthe pres-'-ent invention is to provide for keeping the bear ings at a relativelylow even when the invention may be obtained either by a structurewhichis functioning at all timeslor by a structure which becomesoperative upon failure of the driving mechanism for the blower.

Other. and further objects and advantages of the invention willhereinafter more fully appear from the following detailed descriptiontaken in connection with the accompanying drawings in which-- I V in thesleeve, the blower is not in operation. fIhis-feature of i deviceembodying the invention, showing the device imposition in the wall of anannealing furpace.

Fig; 2 is a horizontal sectional view along the line 1-4 of Fig. 1.

{Fig. 3 is a sectional view similar to Fig. 1,

showing a modification.

. Fig. 4 is a fragmentary sectional view on a glarger'scale, of a partof Fig; 3.

,Like, reference characters refer to like parts inthedifierent figures.

Referring first to Fig. l, the device of the invention comprises a baseI by which the blower ismounte'd in the wall of a chamber, such as afurnace or oven, as will hereinafter appear. The basel has'connectedthereto a main homing 2 ,-.which is positioned within the base'and hasproiecting lugs 3 by which the base and housing are held inpredeterminedrelation. Bolts 4, extend- I ing through'thelugs secure the base andhous- .-ing together, the latter being spaced from'the base to define anannular air passage 5,

-The frame 6 of an electricrnotor is mounted "on the lower-end of thehousing 2 and comprises the end caps 1 and 8 between which is clampedthe stationary winding 9 of the motor. The caps I and '8 are suitablysecured, together,

as by bolts, not shown, and thetmotor frameis secured by bolts II to thehousing 2, the bolts H passing through lugs I2 on the cap I. The endcaps"! and 8 have antifriction bearings l3. and

I which supportthe driving Shaft 1510f the blower. The rotor [6 of. themotor} is secured Jto'theshaft l5, and the shaft is' accordingly drivenat a suitable rate of speed by themotor.

shaft [5 projects upwardly ffromv the motorthrough an opening I1.atthezupper endof the housing 2, the latter ilbeingi substantiallylargerin diameter than the shaft, and'ithence through a sleeve l8forming an integral part of the base L. The circulatingfan jl'ii issecured to the endof the shaft l5, vwhiz'zh'p'rojects beyond the end; ofthe'sleeve, a clamping nut 20 holding the fan securely on the end-oftheshaft.

It willfbe clear that the sleeve .ll-isslightly larger in diameter thanthe shaft Li to permit expansion of the latter, as a-resultfof the heat-"ing -thereof,fwithout engagingwith, or binding Forcooling the motor andshaft adjacent to the*supportingflbearings, av centrifugal cooling fan2|, of anysuitable form,-.is'located on the shaft 15' directly above theopening 1'! inthe housing 2,. being positioned between gsaid .openingand a fiatsannular surface 22 provided bythe base I. The rotation ofthefan thus sets up, through'vanes 23 incorporated in'the fan,

a. flow of air in the direction indicated by the 1 arrows, the air beingdischarged through the annular space provided between the housing 2 andbase I. The suction established by the fan 2i draws cool air in betweenthe frame of the motor and a cylindrical shell 24 secured to anddepending from the housing 2 and the cool air moves upwardly through theannular space or chamber between the housing 2 and the driving shaft forthe fan, thus cooling the motor and the shaft.

For more effective cooling of the driving shaft, the housing 2 hasinwardly extending flanges 25 and 26 between which is positioned a hub21 secured to the driving shaft I5 for rotation therewith. A similar hub23 is positioned between the upper flange 25 and the opening I! in theupper end of the housing. Each of these hubs has radiating fins 23extending radially of the hub for more effective radiation of heat fromthe hubs and shaft and to aid in the circulation of the cooling medium.The hubs are relatively wide adjacent to the shaft and taper to arelatively narrow periphery to aid the flow of air therearound. The hubsare substantially as large in diameter as the inner diameter of theflanges 25 and 26 to cause the air passing upwardly within the housing 2to circulate over the entire surfaces of the hubs.

Each of the hubs has radial channels 30, Fig. 1, therein which are inline'with corresponding channels 3! in the shaft I5. The channels 3|intersect a vertical bore 32 in the shaft I5, the bore extending fromthe lower end thereof to a point adjacent the upper end. In manufacture,it may be desirable to have the bore extend the entire length of theshaft and a suitable plug placed in the upper end thereof. The rotationof the hubs 21 and 28, together with the suction established by the fan2I, causes a movement of air upwardly through the bore 32 in the shaftI5 and discharges it through the channels 30, thereby effectivelycooling the shaft to a point above the upper bearing for the shaft. Inaddition, the shaft I5 may have radial channels 33 intersecting the bore32 in alinement with the fan 2I.

The circulating fan I9 is frequently intended to operate in anatmosphere of inert gas and to prevent the cooling air from passingupwardly between the shaft I5 and the sleeve I8, the upper plate 34,which forms a part of the cool ing fan 2|, has small perforations 35, sothat the space between the shaft and the sleeve I8 is maintained under aslight vacuum, with theresult that no air passes upwardly into thechamber in which the fan is located. The amount of inert gas enteringthe blower from the furnace is negligible because of the relativelyslight vacuum. Any suitable means, not shown, may be provided forassuring a supply of grease to the bearings at both ends of the motor.

One example of an installation where a fan of the character abovedescribed would be espe cially useful is best shown in Fig. 1. Referringto this figure, the base I of the device is pos'itioned within acylindrical opening 36 in the bottom wall 31 of a suitable chamber,which in the drawings is an annealing furnace, being held therein bybolts 38 passing through a flange 39 on the base. The bottom wall 31 hasplates of insulating material and within the annealing furnace arelocated annular rings 40 of suitable insulating material, on the top ofwhich the material tobe annealed is positioned. The material, in theparticular embodiment shown, is coils of wire which are stacked onsupports 4| on theannular rings. An annular hood 42 covers the materialto be annealed and suitable means, not shown, provide for heating thegas within the hood. The fan I2 directs the inert gas in a circularpath, the gas passing upwardly along the inside of each coil of wire anddownwardly adjacent the outside of the chamber, being directed back tothe underside of the fan through the channels 43 provided in one of thesupporting rings 43. By the provision of a positive current of gaswithin the furnace, it is possible to assure a uniform heating of thematerial within the furnace without overheating of any portions thereof.At the same time, although the fan which establishes the gas currents isin an atmosphere of extremely high temperature, the provision forcooling the driving shaft of the fan is such that the driving shaft andthe mechanism associated therewith does not become sufficiently hot atthe bearings thereof to affect the operation of the blower inany waywhatever. It will be noted that the blower provides for the circulationof the cooling fluid without the necessity for any auxiliary apparatusfor circulating the cooling fluid.

The fan I9 for the circulation of the inert gas within the furnace maybe of any suitable character, but is shown as an impeller type havingvanes 44,- Fig. 2, cooperating with similar vanes 45 on an annular ring46 mounted on one of the annular insulating rings 40. The vanes 44 arepositioned between the hub 41 of the fan and an annular ring 48, whichacts as a guide for the gas currents. A corresponding ring 49 integrallyconnected to the base Iby webs 50 cooperates in guiding the inert gaswithin the furnace through the fan.

The blower has been shown in connection with one specific form ofannealing furnace, but it is equally applicable to other installationswhere the circulating fan must be located in an atmosphere of relativelyhigh temperature which would affect the operation of the blower if noprovision were made for cooling.

With reference now to Fig. 3, which shows a modified form of the device,the base 5| is mounted within the wall of the furnace or oven in amanner similar to that of the base I above described. A driving motor 52is secured to the base, as by lugs 53, which are integral with one ofthe end caps 54 and 55 between which is clamped the stationary winding56 of the motor. The lugs 53 are connected to the base by suitable bolts51.

A housing 58 surrounds the motor in spaced relation thereto to define anannular passage therebetween, and the upper portion 59 of the housing isspaced from the base 5| to define an annular passage outside of thehousing. The housing is secured as by rivets 60 and il to the lugs 53.

The end caps 54 and 55 of the motor are provided with suitableanti-friction bearings 62 and 63 which support the drive shaft 64 of themotor. The rotor 35 is mounted on the shaft 64 and the latter isaccordingly rotated at the desired rate by the motor.

The shaft 64 projects upwardly from the motor and has a flanged ring 65secured to the end thereof, as by being shrunk on the shaft, anddirectly below the flanged ring is mounted a cooling fan 61. The fancomprises an upper disk 68 secured to the flanged ring, a flat lowerdisk 69 having a large central opening 10 and vanes ll extending betweenthe two disks. The disk 69 8 is positioned just above the centralopening I2 clamping nut 16. The shaft extends down-- wardly through acentral opening 11 in the upper end of thebaseL-SI' and also through asleeve l8 which extends upwardly from the opening 11. Suitable packing19 may be provided within the opening II to prevent leakage of hot gasesfrom within the furnace with a gland 80 to hold the packing in position.

- On the lower end of the shaft 15 is mounted a' flanged ring 8| similarto the ring 68, and a disk 82 ,of. solid insulating material ispositioned between the two flanges to hold them in'spacedf relation.-The insulation utilized may beat any. I

suitable character which will withstand the high temperaturesencountered, one form-of this m sulation being that-commerciallyavailable: under the trade '7 name of electrobestos." The disk. ofinsulating material has its outercylindrical; surface 83 machined to fitsecurely within the' axially-extending;.annular flanges 8| and 85 on theflanges ,8] and 88 respectively, ahdthetwo flanges w'iththe insulationtherebetween areheld togetherby suitable bolts 86.

,As bestshown in Fig. 4, the openings t1, in t e flanges '66 and 8|,through which the bolts-.86 extend, are largergin diameter than thebolts, to prevent; the conduction of heat from the upper to the lowerflange, and the heads of the bolts, as well as the nuts on the oppositeends thereof, are insulated from the flanges by small .washers 88 ofinsulating material, preferablyof the same character as that formingthedisk 82.

Thus the shafts I5 and 85 are held in accurate alinement with each otherand function as a unitary shaft without the possibility of theconduction of any substantial amount of heat along the shaft from thecirculating fan 14 to the bear ings 62 in the motor. The insulating disk82 is effective whether the motor is functioning or at rest, andaccordingly acts as a safeguard in the event of a power failure whichwould otherwise result in damage to the bearings 82.

For further cooling of the bearings and for decreasing the amount ofheat conducted along the shaft 64, the latter is hollow, having acentral bore 89 open at both ends thereof. The disk 82 hasradiallyextending openings 9|], which, during a rotation of the shaft, providefor an outward movement of the air through the passages by reason ofcentrifugal force, thereby providing for a constant inflow of cool airthrough the opening in the lower end of the shaft and for a discharge ofair into the base around the outer ends of the passages 90. The

amount of heat conducted from the circulating fan 14 downwardly towardthe motor may be further decreased by providing the shaft 15 with f acentral bore 9|, the lower end of which is of metal for transmittingheat is greatly decreased'when the shaft is hollow. I s,

By this structure the bearing 82 is kept cool at all times when themotor is functioning, since the fan provides for a circulation of coolair around the bearing, and since the radial openings provide for amovement of cool air 5 through the shaft 64. In the event that the motorfails to operate, the bearing 82 will still be protected againstoverheating since the disk of insulating material 82 will resist thetransfer of heat from the upper shaft 15 to the lower lo shaft 64 andprevent any damage to the hearing.

The structure of Figs. 1 and 2 may be similarly protected againstoverheating upon failure of the motor to function. To this end a cap 93is mounted on the lower end of the end cap 8 16 through the medium of adisk 84 which has packing 95 therein. Suitable bolts, not shown,

may hold the cap and disk in position. The

cap has an upwardly extending nozzle 96 which extends into the end ofthe bore 32 in the shaft 20 IS. The nozzle is smaller than the bore sothat there is a passage between the nozzle and the bore for thedischarge of cooling fluid directed within the. shaft by the nozzle andthe pressure of th'ejcooling fluid issu'ch thatthe nozzle dis- 25chargesfluid upwardly to a point between the upper bearing l8andthelowerm'ost radial channel in the shaft, l5 A supply of coolingfluid is provided by a conduit 91 connected to a port 88 in the cap 98and the supply of cooling fluid 80 is controlled by a valve 98' which isnormally closed and held closed by a solenoid 99 connected in the powersupplyfor the motor. Upon failare of the power supply, the solenoid isdeenergized and the valve 98 automatically opens so 35 that the. coolingfluid will'be directed upwardly within the shaft 15. An opening Hill isprovided in one side of the cap for the discharge of the cooling fluidflowing out of the shaft.

While the blower is operating, air is circulated 40 through the chamberdefined by the housing 2, the latter acting as a partition to deflne theannular chamber around the radial hubs 21 and 28. The housing 2 isspaced from the base i to deflne a passage which communicates at itsupper 45 end with the chamber inside of the housing 2, and this passageis in effect a continuation of the chamber within the housing so thatair drawn upwardly through the chamber by the fan 2| can be dischargedoutwardly through the. 50

passage between the housing and base.

From the foregoing, it will be apparent that the device functions tomaintain the bearings cool during fan rotation by circulating a coolantaround said bearings or through the shaft to a 55 point between thebearings and the fan. A further protection is the provision forpreventing transfer of heat to the bearings when the motor is notrotating, either by circulating a cooling fluid through the'shaft, as inFig. 1, or by break- 60 ing the shaft and inserting insulation betweenthe fan and the adjacent hearing. The shafts 84 and I5 are functionallyintegral, being rigidly connected together where the insulation isinserted,

and, function asa single shaft. Thus, in ceras tain of the claims, theterm shaft includes the alined shafts 64 and I5, as will be apparent.

We claim: I

1. A blower, comprising a housing adapted to be positioned in the wallof a chamber within 70 which hot gases are located, a shaft joumalled insaid housing with its inner end extending beyond the housing and intothe chamber, a fan on said inner end, bearings provided by the housingfor the shaft, radial fins on the shaft, said 7 housing having apartition defining *a second chamber closely surrounding the fins andwithin which the fins are positioned, said partition also defining apassage communicating with the outside of the first chamber andextending from the end of the second chamber adjacent to the fan, andmeans on the shaft for circulating a cooling fluid through said secondchamber and passage.

2. A blower, comprising a housing adapted to be positioned in the wallof a chamber within which hot gases are located, a shaft journalled insaid housing with its inner end extending beyond the housing and intothe chamber, a fan on said inner end, bearings provided by the housingfor the shaft, said shaft being hollow from the end opposite the fan toa point between the fan and the adjacent bearing, a partition forming apart of said housing and defining a second chamber surrounding the shaftand communicating with the atmosphere outside of the first chamber andmeans on the shaft for circulating a cooling fluid through said shaftand discharging the fluid into said second chamber.

3. A blower, comprising a housing adapted to be positioned in the wallof a chamber within which hot gases are located, a shaft journalled insaid housing with its inner end extending beyond the housing and intothe chamber, a fan on said inner end, bearings provided by the housingfor the shaft, said shaft being hollow from the end opposite the fan toa point between the fan and the adjacent bearing, a second fan on saidshaft, the latter having openings to cause circulation of air fromwithin the shaft to the outside thereof as the fan operates, a chambersurrounding said shaft, and fins on said shaft within the chamber, saidsecond fan causing a movement of cooling fiuid through said chamber.

4. A blower adapted for the circulation of hot fluids, comprising ahousing adapted to be positioned in the wall of a chamber within whichthe fluids are circulated, bearings provided by said housing, a shaftjournalled on the bearings with its inner end extending into thechamber, a fan on said inner end, said shaft being hollow from the endopposite the fan to a point between the fan and the adjacent bearing,radial fins on the shaft between the fan and the adjacent bearing, saidhousing having a partition defining a chamber within which the fins arepositioned, and a second fan on the shaft for circulating cooling airaround the fins, said shaft having openings therein adjacent to the finsand intersecting the hollow center of the shaft, whereby said second fanprovides for a movement of cooling airthrough the shaft and out theopenings as well as around the fins.

5. A blower, comprising a housing adapted to be positioned in thewall ofa chamber within which hot gases are located, a shaft journalled in saidhousing and extending into said chamber, bearings for said shaft, a fanon the end of said shaft, said shaft having a bore extending from theend opposite to the fan to a point between the fan and the adjacentbearing, means for circulating a cooling fluid through said, bore inresponse to rotation of the fan, and other means operative when the fanis not rotating for circulating a collant through said bore.

6. A blower, comprising a housing adapted to be positioned in the wallof a chamber within which hot gases are located, a shaft journalled insaid housing, bearings for said shaft, a fan within the chamber andconnected to the shaft, means for circulating a coolant through theshaft adjacent to the bearings in response to rotation of the shaft, andmeans operative when the shaft is not rotating for keeping the shaftcool adjacent to the bearing nearest to the fan.

'7. A blower, comprising a housing adapted to be positioned in the wallof a chamber within which hot gases are located, a shaft journalled insaid housing, bearings for said shaft, a fan within the chamber andconnected to the shaft, means for circulating a coolant through theshaft adjacent to the hearings in response to rotation of the shaft, andmeans operative when the shaft is not rotating for keeping the shaftcool adjacent to the bearings, said last means comprising an insulatingdisk positioned in the shaft between the fan and the adjacent bearing.

8. A blower comprising a housing adapted to be positioned in the wall ofa chamber within which hot gases are located, a shaft journalled in saidhousing with its inner end extending beyond the housing and into thechamber, a fan on said inner end, bearings provided by the housing forthe shaft, at least one radial fin on the shaft, said housing having apartition defining a second chamber closely surrounding said fin, and asecond fan on the shaft between the first fan and the fin forcirculating a cooling fluid through said second chamber, said partitionalso providing a return passage from the second fan to the atmosphereoutside the first chamber.

9. A blower comprising a housing adapted to be positioned in the wall ofa chamber within which hot gases are located, a shaft journalled in saidhousingwith its inner end extending beyond the housing and into thechamber, a fan on said inner end, bearings provided by the housing forthe shaft, said shaft being hollow from the end opposite the fan to apoint between the fan and the adjacent bearing, and a second fan on saidshaft, said shaft having openings therein to cause circulation of airfrom within the shaft to the outside thereof as the second fan operates,said housing having a partition defining a second chamber communicatingwith the atmosphere outside the second chamber and into which the airfrom within the shaft is discharged.

10. A blower adapted for the circulation of hot fluids, comprising ahousing adapted to be positioned in the wall of a chamber within whichthe fluids are circulated, bearings provided by said housing, a shaftjournalled on the bearings with its inner end extending into thechamber, a fan on said inner end, said shaft being hollow from the endopposite the fan to a point between the fan and an adjacent bearing, atleast one radial fin on the shaft between the fan and the adjacentbearing, said housing having a partition defining a second chamberclosely surrounding the fin and within which the fin is positioned, anda second fan on the shaft for circulating cooling air around the fin andthrough the second chamber, said shaft having openings therein adjacentto the fins and intersecting the hollow center of the shaft, wherebysaid second fan provides for a movement of cooling air through the shaftand out the openings as well as around the fins, said second chambercommunicating at opposite ends with the atmosphere outside the firstchamber.

OTTO WECHSBERG.

HELMU'I' WERNER.

